1. Field of the Invention
The present invention is directed to an ultrasound array consisting of a plurality of oscillator elements disposed side-by-side, and to a method and apparatus for manufacturing such an array.
2. Description of the Prior Art
German OS 28 29 570 discloses in FIG. 5 an ultrasound array consisting of a plurality of oscillator elements side-by-side, each oscillator element having opposite faces coated with electrode material, thereby forming first and second electrode surfaces. The second electrode surface of each oscillator element is disposed in a base region connecting all of the oscillator elements. The side faces of the oscillator elements, extending between the first and second electrode surfaces, proceed non-parallel to each other so that each oscillator element has a trapezoidal (wedge like) cross-section. The oscillator elements are attached to a common damping member. Two types of oscillator elements are used in alternation. In one type of oscillator elements, the trapezoidal cross-section is oriented so that the widest portion is closest to the damping member, with the oscillator element tapering to a narrowest width as the distance from the damping member increases. In the other type of oscillator element, the narrowest portion is closest to the damping member, and the element widens with increasing distance from the damping member.
It is also known from German OS 28 29 570 that an ultrasound array having a fine division of the individual transducer elements can be manufactured by a sawing technique, for example using a laser cutting beam.
Such an ultrasound array is not suitable for use as a phased array applicator because the two types of oscillator elements disposed side-by-side have different emission characteristics. The width of the emission face of each oscillator surface must be smaller than or equal to .lambda./2, whereby .lambda. is the wavelength of the emitted ultrasound in the propagation medium. This condition cannot be met, or can be only unsatisfactorily met, in an ultrasound array having two different types of oscillator elements.